Flexible duct with sealed insulation for aircraft applications

ABSTRACT

A hose for transport of conditioned air between a ground-based heating-ventilating unit and an internal ventilation system of an aircraft comprises at least one hose segment. The hose segment has an end provided with a fastener interconnectable with a fastener on an end of an adjacent hose segment. The hose segment also has an interior insulation layer sealed to inhibit migration of moisture between the insulation layer and the interior of the hose.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation in part of U.S. patent application Ser. No. 09/248,431 filed on Feb. 11, 1999, which claims the benefit of U.S. Provisional Application No. 60/074,623, filed on Feb. 13, 1998.

BACKGROUND OF INFORMATION

[0002] 1. Field of the Invention

[0003] The invention relates generally to interconnectable, insulated flexible ventilation ducts. More specifically, the invention relates to air ducts for transporting conditioned air.

[0004] 2. Related Art

[0005] During the time an aircraft is located adjacent to an airport gate, conditioned air can be transported to the aircraft from a ground-based heating or air conditioning system. This is done through the use of insulated flexible duct that connects the heating or air conditioning unit of the airport with the internal ventilation system of the aircraft.

[0006] These ducts have been manufactured with various materials and in varying lengths to accommodate different types of aircraft. They are typically formed of several segments connected together through releasable connections. Depending upon the type of the aircraft being serviced, it is necessary to add or delete segments of the duct to establish a suitable and appropriate connection of the aircraft ventilation system with the ground-based unit. The releasable connections can comprise zippers or hook and loop fasteners, such as Velcro®. An example of a duct assembly employing hook and loop fasteners to interconnect adjacent segments of the ducts is shown in U.S. Pat. No. 5,368,341 (Larson), issued Nov. 29, 1994.

[0007] It is known to use insulation to retard heat transfer between the interior of the duct and the exterior, since the air is typically conditioned, i.e., either heated or cooled and humidified or dehumidified to a comfortable level. A problem with known insulated ducts is their propensity for the insulation layer to absorb moisture, particularly in warm, humid climates. Passing air picks up moisture in the insulation layer, thus altering its pre-conditioned state. Moreover, heavily moisture-laden insulation diminishes the durability of the duct and renders it more difficult to maneuver. This often happens particularly where open cell foam is used as the insulating layer, or where the insulating layer is exposed to the exterior, such as through a stitched seam or through abrasions in the exterior sheath. The need exists for more durable ventilation duct, given the harsh rigors of its typical use on airport ramps, along with a need for a greater degree of protection for the insulation and for the connections.

SUMMARY OF INVENTION

[0008] This invention relates to a hose for delivery of conditioned air between a ground-based heating-ventilating unit and an internal ventilation system of an aircraft. The hose has at least one hose segment having an interior layer of insulation. The insulation has a surface sealed against migration of moisture into or out of the insulation layer. Thus, migration of moisture into the interior of the hose through the insulation layer is inhibited.

[0009] In one aspect, the surface is sealed by a sealing agent. Preferably the sealing agent is polyurethane which can be sprayed on the interior surface. In another aspect, the sealing agent is a film, preferably polyolefin.

[0010] The insulation itself can comprise an open cell foam. And may have two surfaces where one or both are sealed. One of the surfaces would be exposed to the interior of the hose where the conditioned air passes.

[0011] In another aspect, the invention is directed a combination of at least two hose segments. Each hose segment has an end with a fastener connectable with an adjacent fastener on an adjacent hose segment. At least one protective flap is preferably located adjacent the fastener on one hose segment and is preferably adapted to cover the fastener and an interconnected fastener when a pair of hose segments are connected to each other. A sealed insulation layer surrounds the interior of each hose segment.

[0012] Other objects, features, and advantages of the invention will be apparent from the ensuing description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0013]FIG. 1 is a perspective view showing the air duct according to the invention shown extending between an airport terminal ventilation system and an aircraft.

[0014]FIG. 2 is a fragmentary perspective view of interconnected segments of the duct of FIG. 1.

[0015]FIG. 3 is an exploded perspective view showing adjacent segments of the duct of FIG. 1 with arrows showing the interconnection of the ends of the adjacent segments.

[0016]FIG. 4 is a perspective view showing a first stage of interconnection between the ends of the two adjacent segments of FIG. 3.

[0017]FIG. 5 is a perspective view showing a nearly complete interconnection between the ends of the adjacent duct segments of FIG. 4.

DETAILED DESCRIPTION

[0018] Turning to the drawings and to FIG. 1 in particular, a air duct 10 for transporting conditioned to an aircraft 12 is shown comprising several interconnected segments 14, the ends of which are serially joined together by closure connections 16. It is understood that the number of segments actually needed will vary depending on a number of factors such as the size of the aircraft and the proximity of the aircraft to the gate. Indeed, if the segment is long enough, or the distance between the aircraft and the gate is short enough, only a single segment will be needed. For this invention, it is assumed that at least one segment will be needed. The size of each segment is limited by its manual transportability and the ease with which it can be stored, unstored and connected to ventilation systems and/or adjacent segments. When the duct segment or segments 14 are in place, conditioned air can be carried from a ventilating system 18 typically located within an airport to an internal ventilating system (not shown) of the aircraft 12 on a ground surface 20 before the aircraft 12 is ready for takeoff. Interconnection of the internal ventilation system of the aircraft 12 to the ventilating system 18 on the ground 20 allows the internal ventilation system of the aircraft 12 to cease generation and delivery of conditioned air to any occupants of the aircraft 12 and permits the aircraft engines to be shut down. Rather, the conditioned air is supplied from the ventilating system 18 of the airport.

[0019] Looking now at FIGS. 2 and 3, each duct segment 14 has an exterior sheath preferably manufactured from a vinyl material, such as coated nylon, which affords optimum strength and flexibility in all types of weather conditions and temperatures. Each segment 14 is formed from a single rectangular length of the duct material joined along opposing longitudinal sides 22 thereof by a longitudinal seam 24. The seam 24 is preferably welded to provide maximum tear-resistance and prevent the escape of any conditioned air carried within the duct 10, and a longitudinal strip 25 of similar material can be welded over the longitudinal seam 24 to provide additional protection. Of course, with the protective longitudinal strip 25, the longitudinal seam can be formed in other ways, such as by stitching. An insulation layer 27 is disposed interior to the duct adjacent to the exterior sheath primarily to retard heat transfer between conditioned air passing through the duct and the exterior atmosphere. The insulation layer 27 may be formed of closed cell foam to minimize water absorption. More often, however, open cell foam has been found to be more cost-effective. The duct 10 is flexible, especially radially, to permit deformation of the duct 10 so as to be flat on the ground surface 20. Thus, ground vehicles can be driven over the duct 10 without permanent damage to the duct. Moreover, the duct itself can be rolled up for storage.

[0020] Each segment 14 has a first end 26 and a second end 28. The first and second ends 26 and 28 each carry closure connections 16 which enable a second end 28 of an adjacent segment 14 to be interconnected to the first end 26 of another segment 14 of the duct 10, or, alternatively, either to an airport ventilation system or to an aircraft. Closure connections 16 include any type of fastener that would secure the connection against axial separation, such as zippers, snaps, hook and loop, and the like.

[0021] In a preferred embodiment, the connections 16 on the first end 26 of each segment 14 includes a first portion 30 of a zipper used for interconnecting adjacent segments 14 of the duct 10 which preferably extends substantially around the circumference of the first end 26. A first portion 32 of a hook and loop fastener, such as Velcro®, is located adjacent to the first portion 30 of the zipper and preferably axially inwardly thereof.

[0022] The second end 28 of each segment 14 includes a second portion 34 of the zipper which is adapted to interconnect with the first portion 30 of the zipper on the first end 26 of the segment 14. The second end 28 of the segment 14 is also provided with several flexible flaps 36 extending axially outwardly of the second portion 34 of the zipper.

[0023] Each flap 36 includes an interior surface 38 provided with a transversely-extending second portion 40 of the hook and loop fastener that is adapted to removably engage the first portion 32 of the hook and loop fastener on the first end 26 of an adjacent segment 14.

[0024] Each flap 36 also includes a first end 42 and a second end 44. The first end 42 of each flap 36 has a first portion 46 of a hook and loop fastener provided on the interior surface 38 of the flap 36. The second end 44 of each flap 36 is provided with a second portion of a hook and loop fastener on an exterior surface 50 of the flap 36.

[0025] The flaps 36 are preferably formed as circumferential extensions of the second end 28 of the segment 14 whereby a first end 42 of one flap 36 is adapted to overlap a second end 44 of an adjacent flap 36. The first portion 46 of the hook and loop fastener on the first end 42 of one flap thereby overlaps and engages the second portion 48 of the hook and loop fastener located on the second end 44 of an adjacent flap 36 as shown in the drawings.

[0026] Although three flaps 36 are shown in the drawings, it will be understood that additional or fewer flaps 36 can be provided to the second end 28 of the segment 14 without departing from the scope of this invention.

[0027] In the illustrated assembly, the first end 26 of one segment 14 is brought adjacent to the second end 28 of an adjacent segment 14 as shown in FIG. 4. The first portion 30 of the zipper on the first end 26 of one segment 14 is engaged with the second portion 34 of the zipper on the second end 28 of the other segment 14. The zipper is then circumferentially traversed so that the first and second portions 30 and 34 thereof are interengaged. Thus, the primary function of the zipper, and specifically the first and second portions 30 and 34 thereof, is to securely interconnect the first and second ends 26 and 28 of adjacent duct segments 14.

[0028] The flaps 36 located on the second end 28 of the segment 14 have the primary purpose of providing a protective cover to prevent environmental elements from damaging the first and second portions 30 and 34 of the zipper. Once the first and second portions 30 and 34 of the zipper on adjacent segments 14 are interengaged, the flaps 36 on the second end 28 on one segment 14 can be folded toward the first end 26 on the adjacent segment 14 so that the second portion 40 of the hook and loop fastener located on the interior surface 38 of each flap 36 overlaps and engages the first portion 32 of the hook and loop fastener located on the first end 26 of the adjacent segment 14. The flaps 36 thereby enclose the first and second portions 30 and 34 of the zipper.

[0029] The first portion 46 of the hook and loop fastener located on the first end 42 of each flap 36 can also be engaged with the second portion 48 of the hook and loop fastener located on the second end 44 of the adjacent flap 36 so that each of the flaps 36 are engaged with a successive and a preceding flap 36 as well as with the first end 26 of the adjacent segment 14. Thus, the interengagement of each of the successive and preceding flaps 36 in connection with the engagement of each flap 36 with the first end 26 of the adjacent segment 14 forms an impermeable enclosure for the first and second portions 30 and 34 of the zipper.

[0030] It will be understood that the seam 24 is preferably welded whereby the material on one longitudinal side 22 of the rectangular piece of duct material is bonded with the material on the other longitudinal side 22 of the piece. It has been found that the welded seam has greater strength than conventional stitch seams as well as not being subject to unraveling due to abrasion, such as when the duct 10 is dragged across the ground surface 20 during use. More importantly, the welded seam more effectively inhibits penetration of moisture from the exterior of the sheath. This especially so when the longitudinal strip 25 is welded over the seam, providing an additional layer of protection.

[0031] It has also been found that coupling the first and second ends 26 and 28 of adjacent segments 14 of the duct 10 with a zipper eliminates decoupling of the adjacent segments 14 during use. Further, covering the first and second portions 30 and 34 of the zipper with the flaps 36 keeps the first and second portions 30 and 34 of the zipper clean and easy to operate even in inclement weather conditions. Engagement of the flaps 36 with the first end 26 of an adjacent segment 14 as well as with immediately preceding and succeeding flaps 36 provides a secure protective cover to the first and second portions 30 and 34 of the zipper. Although a zipper is thought to more securely attach adjacent segments, it will be understood that a zipper is not a requirement for this invention.

[0032] The foam insulation is preferably bonded to the outer ply of waterproof fabric with a well-known bonding agent such as a hot melt adhesive. Thus, the duct 10 is lightweight while preventing conditioned air from escaping from within the duct 10 or between the interconnection between the first and second ends 26 and 28 of adjoining segments 14. The insulation is further sealed against moisture invasion by a polyurethane spray on the interior surface of the insulation layer after the insulation is bonded to the outer ply. Thus, migration of moisture between the insulation layer and conditioned air passing through the duct is inhibited. It will be understood that any type of conventional sealant can be applied to the insulation layer. Moreover, the application can occur prior to the adhesion of the foam layer to the outer ply, in which case, the sealant can be applied to one or both sides of the insulation layer. For example, a thin sheet of sealing film can be calendared to one or both surfaces of the insulation layer prior to adhering the insulation layer to the outer ply. Polyolefin has been found to be an effective sealing film.

[0033] While particular embodiments of the invention have been shown, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. Reasonable variation and modification are possible within the scope of the foregoing disclosure of the invention without departing from the spirit of the invention. 

1. A hose for delivery of conditioned air between a ground-based heating-ventilating unit and an internal ventilation system of an aircraft, the hose comprising at least one hose segment having an interior layer of insulation, wherein the insulation layer has a surface sealed against migration of moisture into or out of the insulation layer whereby migration of moisture into the interior of the hose through the insulation layer is inhibited.
 2. The hose of claim 1 wherein the surface is sealed by a sealing agent.
 3. The hose of claim 2 wherein the sealing agent is polyurethane.
 4. The hose of claim 2 wherein the sealing agent is sprayed on the interior surface.
 5. The hose of claim 2 wherein the sealing agent is a film.
 6. The hose of claim 1 wherein the insulation layer comprises an open cell foam material.
 7. The hose of claim 6 wherein the film is polyolefin.
 8. The hose of claim 1 wherein the insulation layer has two surfaces and both are sealed
 9. The hose of claim 1 wherein the surface is an interior surface exposed to conditioned air passing through the hose, and the interior surface is sealed.
 10. A hose for delivery of conditioned air between a ground-based heating-ventilating unit and an internal ventilation system of an aircraft, comprising: at least two hose segments, each hose segment having at least one end provided with a fastener connectable with a fastener on an end of an adjacent hose segment; at least one protective flap located adjacent the fastener on one hose segment, adapted to cover the adjacent fastener and a connected fastener when the at least two hose segments are connected to each other; and a sealed insulation layer surrounding the interior of hose.
 11. The hose of claim 10 wherein the insulation layer is sealed by a sealing agent.
 12. The hose of claim 11 wherein the sealing agent is film
 13. The hose of claim 12 wherein the film is polyolefin.
 14. The hose of claim 8 wherein the sealing agent is sprayed on the insulation layer.
 15. The hose of claim 10 wherein the insulation layer comprises an open cell foam material. 